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bte.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 2000-2007 Silicon Graphics, Inc.  All Rights Reserved.
 */

#include <linux/module.h>
#include <asm/sn/nodepda.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
#include <asm/sn/sn_cpuid.h>
#include <asm/sn/pda.h>
#include <asm/sn/shubio.h>
#include <asm/nodedata.h>
#include <asm/delay.h>

#include <linux/bootmem.h>
#include <linux/string.h>
#include <linux/sched.h>

#include <asm/sn/bte.h>

#ifndef L1_CACHE_MASK
#define L1_CACHE_MASK (L1_CACHE_BYTES - 1)
#endif

/* two interfaces on two btes */
#define MAX_INTERFACES_TO_TRY       4
#define MAX_NODES_TO_TRY            2

static struct bteinfo_s *bte_if_on_node(nasid_t nasid, int interface)
{
      nodepda_t *tmp_nodepda;

      if (nasid_to_cnodeid(nasid) == -1)
            return (struct bteinfo_s *)NULL;

      tmp_nodepda = NODEPDA(nasid_to_cnodeid(nasid));
      return &tmp_nodepda->bte_if[interface];

}

static inline void bte_start_transfer(struct bteinfo_s *bte, u64 len, u64 mode)
{
      if (is_shub2()) {
            BTE_CTRL_STORE(bte, (IBLS_BUSY | ((len) | (mode) << 24)));
      } else {
            BTE_LNSTAT_STORE(bte, len);
            BTE_CTRL_STORE(bte, mode);
      }
}

/************************************************************************
 * Block Transfer Engine copy related functions.
 *
 ***********************************************************************/

/*
 * bte_copy(src, dest, len, mode, notification)
 *
 * Use the block transfer engine to move kernel memory from src to dest
 * using the assigned mode.
 *
 * Parameters:
 *   src - physical address of the transfer source.
 *   dest - physical address of the transfer destination.
 *   len - number of bytes to transfer from source to dest.
 *   mode - hardware defined.  See reference information
 *          for IBCT0/1 in the SHUB Programmers Reference
 *   notification - kernel virtual address of the notification cache
 *                  line.  If NULL, the default is used and
 *                  the bte_copy is synchronous.
 *
 * NOTE:  This function requires src, dest, and len to
 * be cacheline aligned.
 */
bte_result_t bte_copy(u64 src, u64 dest, u64 len, u64 mode, void *notification)
{
      u64 transfer_size;
      u64 transfer_stat;
      u64 notif_phys_addr;
      struct bteinfo_s *bte;
      bte_result_t bte_status;
      unsigned long irq_flags;
      unsigned long itc_end = 0;
      int nasid_to_try[MAX_NODES_TO_TRY];
      int my_nasid = cpuid_to_nasid(raw_smp_processor_id());
      int bte_if_index, nasid_index;
      int bte_first, btes_per_node = BTES_PER_NODE;

      BTE_PRINTK(("bte_copy(0x%lx, 0x%lx, 0x%lx, 0x%lx, 0x%p)\n",
                src, dest, len, mode, notification));

      if (len == 0) {
            return BTE_SUCCESS;
      }

      BUG_ON((len & L1_CACHE_MASK) ||
             (src & L1_CACHE_MASK) || (dest & L1_CACHE_MASK));
      BUG_ON(!(len < ((BTE_LEN_MASK + 1) << L1_CACHE_SHIFT)));

      /*
       * Start with interface corresponding to cpu number
       */
      bte_first = raw_smp_processor_id() % btes_per_node;

      if (mode & BTE_USE_DEST) {
            /* try remote then local */
            nasid_to_try[0] = NASID_GET(dest);
            if (mode & BTE_USE_ANY) {
                  nasid_to_try[1] = my_nasid;
            } else {
                  nasid_to_try[1] = (int)NULL;
            }
      } else {
            /* try local then remote */
            nasid_to_try[0] = my_nasid;
            if (mode & BTE_USE_ANY) {
                  nasid_to_try[1] = NASID_GET(dest);
            } else {
                  nasid_to_try[1] = (int)NULL;
            }
      }

retry_bteop:
      do {
            local_irq_save(irq_flags);

            bte_if_index = bte_first;
            nasid_index = 0;

            /* Attempt to lock one of the BTE interfaces. */
            while (nasid_index < MAX_NODES_TO_TRY) {
                  bte = bte_if_on_node(nasid_to_try[nasid_index],bte_if_index);

                  if (bte == NULL) {
                        nasid_index++;
                        continue;
                  }

                  if (spin_trylock(&bte->spinlock)) {
                        if (!(*bte->most_rcnt_na & BTE_WORD_AVAILABLE) ||
                            (BTE_LNSTAT_LOAD(bte) & BTE_ACTIVE)) {
                              /* Got the lock but BTE still busy */
                              spin_unlock(&bte->spinlock);
                        } else {
                              /* we got the lock and it's not busy */
                              break;
                        }
                  }

                  bte_if_index = (bte_if_index + 1) % btes_per_node; /* Next interface */
                  if (bte_if_index == bte_first) {
                        /*
                         * We've tried all interfaces on this node
                         */
                        nasid_index++;
                  }

                  bte = NULL;
            }

            if (bte != NULL) {
                  break;
            }

            local_irq_restore(irq_flags);

            if (!(mode & BTE_WACQUIRE)) {
                  return BTEFAIL_NOTAVAIL;
            }
      } while (1);

      if (notification == NULL) {
            /* User does not want to be notified. */
            bte->most_rcnt_na = &bte->notify;
      } else {
            bte->most_rcnt_na = notification;
      }

      /* Calculate the number of cache lines to transfer. */
      transfer_size = ((len >> L1_CACHE_SHIFT) & BTE_LEN_MASK);

      /* Initialize the notification to a known value. */
      *bte->most_rcnt_na = BTE_WORD_BUSY;
      notif_phys_addr = (u64)bte->most_rcnt_na;

      /* Set the source and destination registers */
      BTE_PRINTKV(("IBSA = 0x%lx)\n", src));
      BTE_SRC_STORE(bte, src);
      BTE_PRINTKV(("IBDA = 0x%lx)\n", dest));
      BTE_DEST_STORE(bte, dest);

      /* Set the notification register */
      BTE_PRINTKV(("IBNA = 0x%lx)\n", notif_phys_addr));
      BTE_NOTIF_STORE(bte, notif_phys_addr);

      /* Initiate the transfer */
      BTE_PRINTK(("IBCT = 0x%lx)\n", BTE_VALID_MODE(mode)));
      bte_start_transfer(bte, transfer_size, BTE_VALID_MODE(mode));

      itc_end = ia64_get_itc() + (40000000 * local_cpu_data->cyc_per_usec);

      spin_unlock_irqrestore(&bte->spinlock, irq_flags);

      if (notification != NULL) {
            return BTE_SUCCESS;
      }

      while ((transfer_stat = *bte->most_rcnt_na) == BTE_WORD_BUSY) {
            cpu_relax();
            if (ia64_get_itc() > itc_end) {
                  BTE_PRINTK(("BTE timeout nasid 0x%x bte%d IBLS = 0x%lx na 0x%lx\n",
                        NASID_GET(bte->bte_base_addr), bte->bte_num,
                        BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na) );
                  bte->bte_error_count++;
                  bte->bh_error = IBLS_ERROR;
                  bte_error_handler((unsigned long)NODEPDA(bte->bte_cnode));
                  *bte->most_rcnt_na = BTE_WORD_AVAILABLE;
                  goto retry_bteop;
            }
      }

      BTE_PRINTKV((" Delay Done.  IBLS = 0x%lx, most_rcnt_na = 0x%lx\n",
                 BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na));

      if (transfer_stat & IBLS_ERROR) {
            bte_status = BTE_GET_ERROR_STATUS(transfer_stat);
      } else {
            bte_status = BTE_SUCCESS;
      }
      *bte->most_rcnt_na = BTE_WORD_AVAILABLE;

      BTE_PRINTK(("Returning status is 0x%lx and most_rcnt_na is 0x%lx\n",
                BTE_LNSTAT_LOAD(bte), *bte->most_rcnt_na));

      return bte_status;
}

EXPORT_SYMBOL(bte_copy);

/*
 * bte_unaligned_copy(src, dest, len, mode)
 *
 * use the block transfer engine to move kernel
 * memory from src to dest using the assigned mode.
 *
 * Parameters:
 *   src - physical address of the transfer source.
 *   dest - physical address of the transfer destination.
 *   len - number of bytes to transfer from source to dest.
 *   mode - hardware defined.  See reference information
 *          for IBCT0/1 in the SGI documentation.
 *
 * NOTE: If the source, dest, and len are all cache line aligned,
 * then it would be _FAR_ preferable to use bte_copy instead.
 */
bte_result_t bte_unaligned_copy(u64 src, u64 dest, u64 len, u64 mode)
{
      int destFirstCacheOffset;
      u64 headBteSource;
      u64 headBteLen;
      u64 headBcopySrcOffset;
      u64 headBcopyDest;
      u64 headBcopyLen;
      u64 footBteSource;
      u64 footBteLen;
      u64 footBcopyDest;
      u64 footBcopyLen;
      bte_result_t rv;
      char *bteBlock, *bteBlock_unaligned;

      if (len == 0) {
            return BTE_SUCCESS;
      }

      /* temporary buffer used during unaligned transfers */
      bteBlock_unaligned = kmalloc(len + 3 * L1_CACHE_BYTES, GFP_KERNEL);
      if (bteBlock_unaligned == NULL) {
            return BTEFAIL_NOTAVAIL;
      }
      bteBlock = (char *)L1_CACHE_ALIGN((u64) bteBlock_unaligned);

      headBcopySrcOffset = src & L1_CACHE_MASK;
      destFirstCacheOffset = dest & L1_CACHE_MASK;

      /*
       * At this point, the transfer is broken into
       * (up to) three sections.  The first section is
       * from the start address to the first physical
       * cache line, the second is from the first physical
       * cache line to the last complete cache line,
       * and the third is from the last cache line to the
       * end of the buffer.  The first and third sections
       * are handled by bte copying into a temporary buffer
       * and then bcopy'ing the necessary section into the
       * final location.  The middle section is handled with
       * a standard bte copy.
       *
       * One nasty exception to the above rule is when the
       * source and destination are not symmetrically
       * mis-aligned.  If the source offset from the first
       * cache line is different from the destination offset,
       * we make the first section be the entire transfer
       * and the bcopy the entire block into place.
       */
      if (headBcopySrcOffset == destFirstCacheOffset) {

            /*
             * Both the source and destination are the same
             * distance from a cache line boundary so we can
             * use the bte to transfer the bulk of the
             * data.
             */
            headBteSource = src & ~L1_CACHE_MASK;
            headBcopyDest = dest;
            if (headBcopySrcOffset) {
                  headBcopyLen =
                      (len >
                       (L1_CACHE_BYTES -
                        headBcopySrcOffset) ? L1_CACHE_BYTES
                       - headBcopySrcOffset : len);
                  headBteLen = L1_CACHE_BYTES;
            } else {
                  headBcopyLen = 0;
                  headBteLen = 0;
            }

            if (len > headBcopyLen) {
                  footBcopyLen = (len - headBcopyLen) & L1_CACHE_MASK;
                  footBteLen = L1_CACHE_BYTES;

                  footBteSource = src + len - footBcopyLen;
                  footBcopyDest = dest + len - footBcopyLen;

                  if (footBcopyDest == (headBcopyDest + headBcopyLen)) {
                        /*
                         * We have two contiguous bcopy
                         * blocks.  Merge them.
                         */
                        headBcopyLen += footBcopyLen;
                        headBteLen += footBteLen;
                  } else if (footBcopyLen > 0) {
                        rv = bte_copy(footBteSource,
                                    ia64_tpa((unsigned long)bteBlock),
                                    footBteLen, mode, NULL);
                        if (rv != BTE_SUCCESS) {
                              kfree(bteBlock_unaligned);
                              return rv;
                        }

                        memcpy(__va(footBcopyDest),
                               (char *)bteBlock, footBcopyLen);
                  }
            } else {
                  footBcopyLen = 0;
                  footBteLen = 0;
            }

            if (len > (headBcopyLen + footBcopyLen)) {
                  /* now transfer the middle. */
                  rv = bte_copy((src + headBcopyLen),
                              (dest +
                               headBcopyLen),
                              (len - headBcopyLen -
                               footBcopyLen), mode, NULL);
                  if (rv != BTE_SUCCESS) {
                        kfree(bteBlock_unaligned);
                        return rv;
                  }

            }
      } else {

            /*
             * The transfer is not symmetric, we will
             * allocate a buffer large enough for all the
             * data, bte_copy into that buffer and then
             * bcopy to the destination.
             */

            headBcopySrcOffset = src & L1_CACHE_MASK;
            headBcopyDest = dest;
            headBcopyLen = len;

            headBteSource = src - headBcopySrcOffset;
            /* Add the leading and trailing bytes from source */
            headBteLen = L1_CACHE_ALIGN(len + headBcopySrcOffset);
      }

      if (headBcopyLen > 0) {
            rv = bte_copy(headBteSource,
                        ia64_tpa((unsigned long)bteBlock), headBteLen,
                        mode, NULL);
            if (rv != BTE_SUCCESS) {
                  kfree(bteBlock_unaligned);
                  return rv;
            }

            memcpy(__va(headBcopyDest), ((char *)bteBlock +
                                   headBcopySrcOffset), headBcopyLen);
      }
      kfree(bteBlock_unaligned);
      return BTE_SUCCESS;
}

EXPORT_SYMBOL(bte_unaligned_copy);

/************************************************************************
 * Block Transfer Engine initialization functions.
 *
 ***********************************************************************/

/*
 * bte_init_node(nodepda, cnode)
 *
 * Initialize the nodepda structure with BTE base addresses and
 * spinlocks.
 */
void bte_init_node(nodepda_t * mynodepda, cnodeid_t cnode)
{
      int i;

      /*
       * Indicate that all the block transfer engines on this node
       * are available.
       */

      /*
       * Allocate one bte_recover_t structure per node.  It holds
       * the recovery lock for node.  All the bte interface structures
       * will point at this one bte_recover structure to get the lock.
       */
      spin_lock_init(&mynodepda->bte_recovery_lock);
      init_timer(&mynodepda->bte_recovery_timer);
      mynodepda->bte_recovery_timer.function = bte_error_handler;
      mynodepda->bte_recovery_timer.data = (unsigned long)mynodepda;

      for (i = 0; i < BTES_PER_NODE; i++) {
            u64 *base_addr;

            /* Which link status register should we use? */
            base_addr = (u64 *)
                REMOTE_HUB_ADDR(cnodeid_to_nasid(cnode), BTE_BASE_ADDR(i));
            mynodepda->bte_if[i].bte_base_addr = base_addr;
            mynodepda->bte_if[i].bte_source_addr = BTE_SOURCE_ADDR(base_addr);
            mynodepda->bte_if[i].bte_destination_addr = BTE_DEST_ADDR(base_addr);
            mynodepda->bte_if[i].bte_control_addr = BTE_CTRL_ADDR(base_addr);
            mynodepda->bte_if[i].bte_notify_addr = BTE_NOTIF_ADDR(base_addr);

            /*
             * Initialize the notification and spinlock
             * so the first transfer can occur.
             */
            mynodepda->bte_if[i].most_rcnt_na =
                &(mynodepda->bte_if[i].notify);
            mynodepda->bte_if[i].notify = BTE_WORD_AVAILABLE;
            spin_lock_init(&mynodepda->bte_if[i].spinlock);

            mynodepda->bte_if[i].bte_cnode = cnode;
            mynodepda->bte_if[i].bte_error_count = 0;
            mynodepda->bte_if[i].bte_num = i;
            mynodepda->bte_if[i].cleanup_active = 0;
            mynodepda->bte_if[i].bh_error = 0;
      }

}

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